The patient recruitment Core A is responsible for patient enrollment for all projects. The Trauma Burn Service admits over 2000 patients annually, of which, over 1000 are adult trauma patients. Adult trauma patients will be recruited for participation from the Trauma Burn Service for three of the projects. To study sepsis in biliary obstruction, we will recruit patients from the Medical Procedures Unit at the University of Michigan, where over 600 ERCP's are performed annually. The research nurse in conjunction with Drs. Wahl and Arbabi will screen admitted patients after receiving an automated download of admitted trauma patients. For Dr. Su' patients, the ERCP case log willl be reviewed for potential patient suitability for the study. Trauma patients with an Injury Severity Score (ISS) of 15 or higher will be captured as potential participants for studies by Drs. Remick, Opp, and Nemzek. Blood samples will be collected from laboratory "waste" each day in an effort to collect multiple time points. In addition, consenting patients will have 3 ml whole blood drawn twice a week for whole blood stimulation studies. Dr. Nemzek will also collect bronchial aspirates from ventilated patients for the first 3 days of their admission. Those patients identified with aspiration events will also undergo bronchoscopy and daily bronchial aspirates by existing clinical protocols. These specimens will be collected and catalogued for patients choosing to participate in the study. For Dr. Opp's portion of the project, the same trauma population with an ISS of > or equal to 15 will be evaluated for enrolment. Consent will be obtained prior to electroencephalogram monitoring. Patients in Dr. Su' project will have blood drawn at the time of ERCP for whole blood stimulation and LBP studies. All clinical data will be captured in a database and combined with laboratory data for the program project. All bedside charting of vital signs and laboratory values currently are available through computerized record systems. APACHE III scoring will be done through existing proprietary software with daily SOFA scores entered into the clinical database.The Trauma Burn Clinical Laboratory (Skin Bank) will be utilized as a staging area for specimen collection and storage. The trauma research nurse and assistant will provide patient identification, enrollment and data collection via the existing trauma registry.